Automatic secret telegraph system



MalCl'l 7, 1933.4 J H. SMART AUTOMATIC SECRET TELEGRAPH SYSTEM Filed Jlanv. l5 1932 3 Sheets-Sheet l 1 10u60? 5A g4. axe) .H 2.@011

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March 7, 1933. J. H. SMART 1,900,772

AUTOMATIC SECRET TELEGRAPH SYSTEM Filed Jan. 15, 1952 s sheets-sheet y2 /N V5 N TOR T U/- ggg s ATTOR V5 Mam 7, 1933- J. H. SMART AUTOMATIC SECRET TELEGRAPH SYSTEM 1932 5 Sheets-Sheet 3 Filed Jan. l5

IH. 5MM/ff i Patentedv Maru 7, 1 933 UNITED s'rn'rias JAMES HENRY SMART, OF SHANGHAI, CHINA.

AUcLoMA'rm SECRET TELEGRAPH SYSTEM' v Application filed January 15,715.132, Serial No. 586,766, and in Great Britain February 4, 1931. i, i, i i

YThis invention relates to automatic teleis to provide an .improved system in which transmitted signals are so mutilated as to become" substantially inde'c'ipherabl'e and yet can be simply and automatically translated at tliereceiving end.

AAnother object of this invention is to render the transmitted impulses substantially indecipher'able by means at the transmitting end adapted to effect an operation which is equivalent to physically turning over or reversing the @tape y at r predetermined "intervals Throughout the specification the perforated tape is referred to as straight When it is the Vright Way up and reversed when it has been actually or in effect turned over so that for example with a lVheatstone type tape) thesignal holes which are normally above the center holes are below the center holes.

`Preferably a perforated tape'bea'ri'ng the message is fed into the transmitter which is so operated at predetermined intervals during the transmission that the signals trans-l mitted are equivalent to those which would be vtransmitted if the tapewere actually turned over or reversed at such intervals.

Yet another object of the invention is to provide a translator for the received multilated; message. Preferably tape bearing such mutilated message is passed through a translator which is operated at the saine predetermined intervals as the Atransmitter to reverse .the effect ofthe tape, and whichcontrols the operation of: a reperforator or other receiver which thus reproduces the original message.

Conveniently a stepping back deviceis embodied in the transmitter which operates after each reversal tO'GauSe a repetition of the by wireless, should be rendered unintelligible a perforatedV vsequence ofthe reversal of the transmission l Y altered,

signals immediately preceding such reversal in order to prevent loss or distortion of sig-A nals due to the reversal. A skipping device is then-provided in the translator-which -op eratesduring each reversal to renderv alength 59 of the tape corresponding to thev amount steppedback by the transmitter inoperative Y so as to eliminate repeated signals.

InV a. preferred arrangement the' transmitter is provided with pecker rods adapted to enf6() A gage signal holes in the tape and operated by v one or other of twocams, the selection'ofthe operating cam being controlled by a key device Whereby the order in which the pecker rods operate at each center hole of the tape '65 is reversed at predeterminedintervals. vThe translator is provided with pecker rods and selector rods adapted to engage signal holes in the tape, the selector'rods 'being arranged to interpolate or neutralize signals so asto Q compensate for the mutilation of the message at the transmitting end..Y Y The following is afdescription by way of example ofa, preferred system accordingto the invention with reference to the vaccompanying drawings, inwhich l' Figures l and la show a short strip ofperforated tape in rits original form and as received when reversed at the transmitting end, Figures 2, 2a and 2b respectively 'show a perforated strip bearing a message, the same strip-reversedand the perforated strip obtained at the receiving endwhen the strip of Y vFigure 2 at the .transmitting end is turned over or reversed before passing through-the transmitter, f l

1Figure lillustrates Adiagrammatica'lly a preferred arrangement of transmitter,

Figure 4 shows a perforated strip as ob- 90 tained at the receiving station for the mesi sage shown in Figure 2 when the transmission is periodically reversed,

`Figure ashows a perforated strip'sim-v ilar to that-shown in Figure 4L but with the '95 Figure .5 Aillustrates diagrammatically a preferred arrangement of translator,

Figures-fgshovvV short lengths of strip illustratingv the varQus conditions to be considered and certain laws governing the f low and above them, the dash.

holes are employed tor positioning Athe tape.

relationships of the holes formnlated. y t

In the short length ot' tape shown in Figure l the signal holes represent a'dot iollowed by radash, i. e. the letter a, the hole' numbered l with the hole 2 immediately below it being the dot and the holes 3 and' G with blankspaces -l and 5 respectively be- T he center and are normally engaged by a star wheel which is rotated to move the tape rstep by step through the transmitter. v

i Asis well known the normal Wlzeatstone transmitter controls the signal impulses sent to line by means of two peckerV rods, which reciprocate alternately, the marking pecker cooperating with the signal holes above `the center holes so that it makes contact to send a mar-king current to line when its end passes through an upper 'or top hole, such as l, andthe spacing pecker cooperating with the signal holes below the center holes so that it makes contact to send a spacing current to line when its end `passes through a lower or bottom hole such 'as 2. After the initiation of a marking current it is sent continuously until the spacing pecker rises through a signal hole to send a spacing current `which again continues untilthe nent time the marking pecker passes through `a signal hole.

When the section ofthe tape shown in Figure 1 is passed through the `lnansmitter it advances step by step from right torle'l't as the star wheel engages .successive center holes. The speed of movement ot the tape depends upon the speed of the star wheel and, for convenience ot' description, tlietiine interval between said successive stepping movements will be referred to as one center hole. `As soon as the tape vis stepped to the `position in whiehthe holes l and 2 are above the peckers the marking pecker rises through hole l to'cause a markingcurrent to be sent toline. Halt a center hole later, the spacing pecker rises through hole 2 to cause a spacing current to be sent to line thus completing the dot. At the end ot the second halit center hole the star wheel moves to advance the tape one step, following which the marking peckcr rises again and passing through hole 3 starts the marking current for the dash. This marking current continues for one and a halt center holes, since there are through hole 3 (indicated by a ycross in Figure lar) will Vnot alter the line current as a spacingcurrent is already being sent. At the next center hole themarking lpecker will risey in hole G and the marking current will be sent which continues `unt-il the next spacing hole (not shown).

the first holeiof the dash, will be missing and this loss of signal holes will often occur when the tape is reversed and engaged bynormal peckers.

, Considering the straight tape shown iny `lhus when a perfor-ating lreceiver is employed'a'hole corresponding rto hole 3, that 1s 1 Fifrure 2 it will be 'seen-that when it is rey versed (Figure 2a) `and sent through the transmitter, the tape obtained `from the receiver will be perforated in the manner shown f in Figureb, the signal holes which are lost being those which are crossed in Figure 2a.

From an examination of Figures 2, 2a and 2?) it will be apparent that each lostlhole must consist either of the first part of a dashA or of the second part of a dot and thus the loss of a complete'dot or dash can never take place` It will also be apparent that with a reversed tape a top-hole always forms the end of a` signal and a bottom hole the beginning.

Thus analyzing the numbered holes in Figure 2b which, as stated above, is the form of the received tape when the tape bearing the original message is reversed before being passed through the transmitter Holes l and 2 are complementary since they form the endf and beginning of a dot. i

Hole 5 is the end of a signal (top hole) but cannot be the end of a dotsince there is no hole at 6. lt must therefore be the end of aidash the beginning of which should be atl. Hence there is a hole missing at 4.

VHole 8 is the beginning of a signal (bottom hole) but it cannot be the beginning of a dash since hole 9 is the complement of hole 10.

Therefore -hole 8 must be the beginning of a dot and there is a hole missing at 7.

Similarly,hole 15 cannot be the end of a dot since there is no hole at 16 and therefore it is the eno of a dash and there is a hole missing From the foregoing considerations it is possible to formulate rules for translating a received reversed tape by means of which all the missing holes can be identified.

These rules are 1. If a top hole has no bottom hole opposite lto it then it must belong to a dash and consequently there should be a complementary bottom hole opposite to the preceding center hole (if there is not one already there), and

2. If a bottom hole is followed by a center hole which has both topand bottom holes or has no holes at all ythen it (the bottom hole) must belong to a dot and should have a complementary top hole opposite to it-(if there is not one already there).

Thus if a tape is run through a transmitter in alternate short straight and reverse lengths there will be many missing signals and the received signals will be indecipherable unless the exact points at which the tape is turned over are known and the rules for filling in the gaps in the'reversed lengths applied at the correct points. s

It will be apparent that in a message the operation of changing-over or reversing may occur at the end of a dot or of a dash, inthe A middle of a dash or in a space, thus causing varyin g mutual relationships between the signal or part of a signal just completed and the next signal to be sent. As a result it sometimes happens that signals are lost during or as a result of the reversal which cannot be supplied by a translatorbased on the two rules given above. For example, referring again toV Figures l and la, assume 'reversal takes place in the middle of a dash, that is afterthe spacing pecker has risen for space 4 but before the marking pecker rises for space 5. Whenreversal takes place there is a marking current flowing to'line due to the marking pecker having risen in hole 3 Figure l) and there being aV blank at4 (Figure l) which prevents the spacing pecker rising.

llr inmediately following the reversal the' marking pecker rises in hole 6 (Figure la) but, since a marking current is already being sent,

, vthe line current remainsunchanged. Hence on the received tape thehole 6 (Figure la) which should be at the beginning ofthe `reversed length is lost, It will be apprefciated that in order to prevent the lossl or mutilation ofl signals at reversal it is neces-V sary to arrange Ythat immediately'following reversal the `line current is in the correct sense` i. e. is in the sense in which itwould have been had the part of the tape before the actual reversal been itself reversed. Thus in the aboveexample the line current at lthe beginning of the reversed length must be aV spacing current in order that the marking pecker rising in hole 6 (Figurela) may be effective.

To ensure that whatever happens at reversal it will always be possible to supply the missing signals it is only necessary to step back the tape one center Y.hole.immediately following reversal so that the signal holes (it any) of the two center holes (the one stepped back and the one actually engaged prior toA reversal) are reengaged at the beginning of the new length. The signals (if any) at these two center holes are thus'repeated at the beginning of the reversed length and although they may be themselves mutilated it is immaterial, since they are correctly produced at the end of theold length. They serve howeverto ensure that the true beginning of the reversed length is correct land at the receiving end, the translator can be arrangedto eliminoriskrof a falseorgmissing signal at the beglnning of a new length following a reversal.

,'75, nate these repeatedrsignals. l:[hus there is L. In practice itis of course not possible to turn over the tape literally even at comparatively long intervals 'and thus according-to this invention the transmitter is operated at predetermined intervals so that the signalsV transmittedV are equivalent to those which would be transmitted' if the strip were actually turned over Vat such intervals'.

In the preferred form of transmitter the essentialy parts of which. are illustrated dia# gramniati'cally in Figure 3, the supporting framework being omitted in order to simplify thetigure, the tape (not shown) is advanced step by step by a star wheel B mounted on a shaft B1.Y The shaft B1 is stepped round in a counterclockwise direction to advance one centerhole for each revolution of the shaftD. In order to'` step back the' tape a secondvratchet'wheel E havinnr a, awl El is arranged so as to VdriveV the shaft B1 in a clockwise ydirection,lthe pawl E1 being roperated by an armE'f? having a roller E? which engages a secondcam E4 alsomounted on the shaft D. The cam E4 has 'a recess E5 arranged so thatthe pawl El can vbe Yoperated to step back the tape one center hole for each revolution of the shaft D.4V 7

The rotation of the shaft B1 by one or other of the ratchet wheels C and E is controlled i a pivoted stop F'which engages one or other of the arms C? andEgso asto hold'theroller thereon clear o fits cam'thus permitting the other Y'arm to control the stepping r'oundof the sh aft. The position of the stop vF is reg-` ulatedby an electromagnet F1 which, when it is energized, moves'the stop F into the position in which the lever C? is inoperative and lever E2 opera-tive.v Normally, the electromagnet Fl is deenergized'and the stop'F' is retained'by a spring (not shown) in the'pow sit-ion innwhich it engages arm E2, arm C2 being free to operate its cam, when the shaft D is rotated, so that the tape is fed forwards.

`Pecker rods G and il are arranged below the tape in the usual way, eachV rod being carried on a pivoted lever (G1 or H1) having a spring (G2 or H2) tending to raise the rod and an arm weich cooperates with a `fined Contact (G3 or H2) arranged so that when the rod is free to rise and passes through a signal hole the arm engages the contact to complete an electric circuit. Movement of the rods G and H is controlled by a rocking beam J pivoted at J1 and carrying pins J2 and J3 which engage the levers Gl and H1 respectively so as to permit the rods to rise in turn as the beam is rocked.

When a tape is straight asV it passes through the transmitterthe current impulses sent to line must be such that as soon as the tape is advanced a step the pecker rod G for the top hole in the ease,for eXarnp1e,of a dot) rises first and completes at the contact G3 of its lever G1 a circuit for a marking current to be sent to lin-e and then the pecker rod H for the lower hole rises and reverses the current to cause a sgaeing current to be sent after which the star wheel B advances the tape one center hole.

Inorder to send impulses which are equivalent to turning over or reversing the tape without physically doing this it is necessary7 not only for the pecker rods to rise in the reverse order but also for the currents sent to line by each pecker rod to be reversed. Thus in the transmitter shown in Figure 3 the pecker rod G, which is normally the marking pecker and rises first to complete at its contact G3 a circuit for a marking current to be sent to line, must, to obtain the effect of a reversed tape, rise aft-er the pecker rod Il and complete at its contact G3 a circuit for a spacing current to be sent to line.

The order `in which the pecker rods rise depends upon the relationship between the rocking of the beam J and the rotation of the star wheel B. Accordingly the beam is driven from the shaft D by` one or other of two cams D1 and D2 provided with the raised portions D3 and D'1 which, as willbe more fully described, cause the beam to rock in a counterclockwise direction to permit pecker rod G to rise,iand `recessed portions D5 and D( which cause the beam to rock in a clockwise direction to permitpecker rod H to rise. The cams are mounted on shaft D so that their raised and recessed portions are'spaced 180 apart. Thus with the cams in the position shown'in the figure, assuming the shaft D is rotating in a counte clockwise direction so that the cam C has just advanced the tape one center hole, operation of the beam J by the cam D1 would allow rodG` to rise and then rod H while'operation of the beam J by the cam D2 would allow rod H to rise and then rod G. In each .case both -rods rise and fall before shaft D completes its revolution at the end of which roller, C2 on arm C2y engages the recessed portion C5 of cam C4 and advances the tape another center hole,

Selection of cam DJ: or D2 for rocking they beam J is obtained 4by a slotted link K connected at one end by a rod K1 to a pivoted arm K2 having a roller K3 which engages the cam'D, and at the other end by a rod K4 to a pivoted arm K5 `having a roller K6 which engages the cam D2. A pin J4 on the beam J engages in the slot of the link K and is maintained at one end or the other of the slot by a solenoid. The solenoid has coils M and M2 for controlling the position of a plunger M2 which is connected to the link K by a rod M2, this rod carrying a `contact member M4 adapted to engage one or other of two fixed contacts hl, lvl according to the position of the link.

As shown in the ligure, the link K is in the position for sending reversed signals, i. e. in which the pecker rod H rises before the pecker rod G, since the cam D] only causes the linl-QK to reciprocate about pin J4 while the cam D2 causes the beam J to rock. Energization of coil `M1v of the solenoid moves the linie K so that the pin Jl is at the other end of the slot K1. Thecam D] thenfrocks the beam J while the cam D2 merely reciprof cates the link K so that straightsignals can be sent.

As previously stated the electrical connections must be such that the current sent as a result ofthe rise of-a pecker rod can be reversed. Accordingly the current sent to line and earth, indicated at N and Nllrespectively, is controlled by a sending relay having two coils N2 and N3 connected in opposition and a tongue N4 which, when it engages itscontact N5, sendsa positive or marking current from a battery N 2 to line and vwhen it engages its contact NG sends a negative or spacing vcurrent from the battery N9 to line. The tongue N4 is provided with the usual Yjockey roller N7 to prevent it remaining in an intermediate position when the relay isdeenergized.

The common point NS of the coils N2 and N3 is connected to the contact member M4 and the relay coils are arranged so `that a current flowing through both coils in series has 'no effect while a current flowing through either coil `towards the point NS causes the tongue to move to contact N to send a spacing current to `line and a current flowing through either coil. in adirection away from point N8 causes the tongue to move-to contact to send a marking current.

Considering the operation of the transmitter when the link K is in the position shown in the figure :-Rotation of shaft D allows pocker rod H to rise and, assuming there is a. signal hole, to complete a circuit at its contact H3 so that a current flows from battery N11l through relay coil N2 in av direction awayfrom N8. Energization of coil N2 in this direction causes the tongue N 4 to move to contact N5 to send a marking ing current is sent to line.

f It will be apparent that lwhen the link K is moved to the other position not only is the order in which the peckers rise reversed, as above described, but also the sending relay coil N2 is short-circuited at the-contacts-M4, M6 'and the operating currents How through the coil N3 in such directions that when pecker rod GrV rises through a signalholea marking current is sent tonline and when pecker `H rises a spacing current-is sent to line.

Movement of the link K from right to left, i. e. to the position shown in the ligure,.thus eifects an alteration inthe currents sent by thetransmitter in accordance with the perforations on the tape whichis equivalent to physically reversing or turning over the tape in an ordinary transmitter at the point where the movement of the link takes place. coilsfM and M1 are controlled kby ar relay O having an armaturev O1 which engages its contact O2 to energize coil M for moving the link K into the reverse transmission position and its contact Otto energizecoil M1 for moving the link K into the straight transmission position. The relay O may be Yoperated in any suitable way so as to reverse the-*transmission at predetermined intervals it only being necessary to have some form of key to such reversals which can be used at the receiving station in conjunction with a translator, as will be more fully described hereinafter, in order to restoretlie received mutilated message to its original form.

For example, .the controlrdevice .for Athe i,

t relay O may consisty ot an ordinary 'Vheatstone transmitter-through which is run a; tape having the top and bottom holes spaced Vat the predetermined intervals, a similar tape beingl provided .at the receiving station.

Vith this arrangement `gearing is arranged between tlietransmitters and. is timed so that the peckeis of the control transmittervrise (and cause a change-over) immediately after the cani D1 or the cam D2 has raisednthe second pecker (H or Gr as the case may be) so .as to allow as much time as possible for the change-over and stepping back operations.

Alternatively, any suitable form of disc,

fwheel or chain with adjustable pins or links may be employed which may be set at predetermined intervals y to actuate the` armature O1 mechanically or electro-mechanically.

As stated above it is necessary, in order to avoid loss Vofjsignalsduring change-over, to step back one centre hole and repeat the lsig- V nalssent at the last two centre'holes of each length at the beginning ofthe nei'it'length.r

This is done bythe energization of elctroniagnet F1 in serieswith condenser F 2 during the movement of armature O1 from one tothe other of its contacts. Stop FV is moved to disengagearm-E2 and engage arm C2150 that cam C4 operates ratchet wlieeljE to step back'the star wheel B, and consequently the tape, vone centre hole; 4 As electronfiagnet,F1

VisenergiZed momentarily by the discharge through the condenser F2 only one holeuis stepped back and -the forward feeding-by. cam- VMD4 .is resumed, the peckers rising after the A`change-over4 to repeatv the signals opposite to the-.stepped-back centrehole andthe next Vcentre ,holeywhicln it will be remembered,

were the last ones engaged erationof the control relay.

Figure l shows a tape bearing the received. `mutilated message when the message of Fige ure 2, which i. representsthe words London, /Englanch is reversed after the eleventh centre hole from the begiiiningland thereafter at every tenth center hole, as indicated bythe arrowsA1 in Figure 2, and thefirst length is sent reversed, Y The-A signals -within the rectangles'A2l intFigure l indicate the extra signals received .dueto stepping back the transmission tapeV andmust be eliminated .by the translator at the receiving end. ,The perforated tape of Figure ta shows 'the different efilectvobtainedv on the received tape when the messagefofFigureQis reversed atthe same intervals as ,in Figure 4 but a stra-ight lengthris sent first.

It is now'necessary to consider the means'at the remote end for receiving themessage anda, for translating the mutilated messageso that n it is restored to its.originalformi.Y The ap vparatus required at this end Vconsists ofan ordinary perforating receiver which may be of the Creed lor any other suitable type and isfy connected to the line so that it receives the incoming mutilated message in the Storm shown in Figures 4 or ta, a translator through which thetape bearing the mutilated niessage is passeda key or keytape device whichv lreverses the'translator at the same intervals prorto theop- ,n

iio

as the transmitter at thesendinglstation isA reversed, and a reperforator simila-rtothe perforating receiver or any othersuitable A. mark ingzor printing receiver to which the corrected impulsesfrom the translator'can be supplied. @Since perforating and marking re-` ceivers are well known it is only necessary-to vdescribe in detail the arrangement and operaf tion ofthe translator and its reversing device, 4, it vbeing assumed that the tape bearingA the mutilated message is fedintothisand the corrected impulsesare supplied to any'csuit-A f ablevreceivernorrecorder. 4 v

I Referring now to Figure i the 'tape yone step, cams -119 and'126release the pecker and selector rods P,R, and P1, R1 so that they are free to rise simultaneously to engage signal holes'in the tape (if any), cam 135 operates jto close the circuit controlled by vthe'piclr-up lever 134, cam 135 operates pickup lever to open its conta-cts and then cams 119 and 126 simultaneously lower pecker and selector rods. This completes they iirst half of the cycle. In the second half of the cycle cams 126 and S1 operate simultaneously frespectively to `permit the Aselectorrods P1, R1 to pass through signal holes in the tape (if any) and to close the circuit controlled vby the spacing level-*133, cam 135 operates to close the circuit controlled by the pick-up lever 134, cam v135 operates pick-up lever to open its contacts and then cams 126 and S1 Y vsimultaneously lower selector rods P1, R1 and operate spacing lever to open its contacts.

This4 completes the cycle and the tape is then advanced another step. 1

During the'operation of thetranslator. a

rodor a selector rod passes through an appropriate signalhole during theiirsthali y corrected message lor to transmit corrected 1 impulses to a reperforator or other recordln'g ,cycle when these'rods 4rise simultaneously, the -pecker rod P and selector rod R1 onlyy being operative when the translator. is set for a straight tape and the peclierrod Rand selector, rod Pl only being operative when the translator is set for a reverse tape as will be more fully described hereinafter, the selector rods acting to interpolate a marking current when there is a marking hole missing in the tape. I AsY the spacing lever 133 is always operatedduring the second half cycle spacing' is obtained. at each centre holeindependently of the` signal holesV in the tape. I Since, howrise a second time simultaneously with the operation. of the lspacing lever act to effect neutralization ofthe spacing current if there is :inappropriate signal in the tape. Selection for astraight or reversed tape is controlled by a relay 4energized from a battery Z1 and having Ya tongue T} which' engages its contact T2 for a straight tape and its contact T3 for a reversedWtapeg .The position oi'f' relay T isvcontrolledebya key c switch T'twhich is operated to effect reversal l'atthe same intervalsas the transmitter-reverses, preferably by means identical to those employed vforcontrolling the reversal of the transmitter'.I Y Aspreviously Ystated'the. ltransin-itter steps `-back onecen'ter hole following reversalY in orderV to prevent the Icompleteloss of afsig` lowing reversal are correctA and are'not lost marking vcurrent is obtained when a peckerr ever, a spacing current isnot required atevery centre hole, the selector rods, when'the'y nal, such as ,might occur, if. reversal took I necessary for the translator to be providedV with means for 'skipping the eXtra holesin the tape due to the steppingv back l,ofthe transmitter, such means being operative to" Ycause skipping ofthe last center hole jbefore change-over and the first center hole'after changeover. A, e ,f

Such means comprlses-the electromagn'et vTwhich, asdescribed above, when ener i gizedmoves the stop 113 clear of the end of the lever 110 so that the tape isvmoved' three Y steps. The electromagnetA T5 is'` arranged'to ybe energized througha condenser T-7 during movementof switch T4 from one to the other 80 of its contacts TS T9, whereby the tape moves forward. threev center holes during change- Y overso as tol skip the tworextra center holes therein due to the stepping back of the transmitter. Y e y I. The lpecker rods YP, R1' and'selector rods P1, R1 control through their contacts P2, P3, P* and R2, RSLR* the operation'of straightand vreverse Astoring relays U andV which in turn control a recording or translating relay ,Y,90 this relay either acting to record. directly the f receiver (not shown).A The translatingre- 7 layv Y is provided vwith a tongueYafcon- Thus when the relay t'ongueY engages'con-1007V tact Y5 a positiveor marking current is sent fto rline while when'the'tongue engages,theA contact Y6 anegative'or spacing currentfis Ysent to line. e l cordingrreceiver isrconnected to thelinesllO i he' reperforator or other re- Yika i I ,:Eaeh storing relay (U or V) is provided' with` differentially woundy lmarking and `spacing coilsy (U1, U2 or V1, V2) supplied from a battery Z through the contacts con-'3110V trolled by thejpeclerand selector rods,- so Y that the currentrpasses through theappropriate coil, and the vtongue (Us or V3 is Ymovedy from one tothe other of its contacts Y (U4, U5 orjV, 'T "The translatingrelayll e Y vis connected to the positive or negative terminal of abatter f Z2'so as to record a markf `ingor spacing current, by one or other of the tongues U3, V3, vas determined lbythe position of the tongue T1 of control relay T. Y 120 `vIn order to prevent clipping or reversing of signals during change-over, as wouldoccur v the storing relays U and V were not both 'sending vcurrent ofthe same `sense 'atftheh p moment of changeiovenythe pick-up levert-12,5 k`131l`lhaving a contact arm'Y1 cooperating V`With-a contact Yzis arranged withv its con` l tacts @in Vseries between the ,tongueTl and the4 relay Y.l As described above the'contact` Y2 is completed twice for each centre'holewo.

`relay Y'signals ofthe correct length.

`and is timedzto ta'keplace once after the,

simultaneous rise of the pecker and selector .rodsand once after the closing ot' the spacing lever S, as indicatedinthe timing diagram 4shown in Figure 7 This arrangement .acts `asiafpick-uplto pass on to thetranslating In the timing diagram shown in Figure 7 the circle represents the timetaken for a complete cycle ot operations between each movement'of the tape, the sectors into which the circle is divided indicating the relative times of the various operations. Thus -b is spacing, b-c pick up, c-d change, cZ-e lt'eed, e-f marking and f-g pick-up.

As a `further safeguard against the clipping of signals each of the storing relays (U and V) is provided-With an additional Winding (UG and V6) which is connected in series between the tongue of the other storing relay yand the contact of the control relay T to which this tongue is connected. Thus -a marking or spacing current due to the operation ot' the Working storing relay passes through the additional Winding of the idle n :D v u n s storing relay, this winding being so arranged that the current causes the idle relay (V in 4Figure 5) to follovv'the movements of the Working relay (U inFigure 5). Thus both relays Will be in position to send current of the samesense to the translating relay Whenever reversal is effected byzth'e operation oi' relayT.

` Two general rules governing the replacing of missingholes have already been formulated, but in order to understand the operation of the translator it is desirableto consider in somewhat greater detail the conditions to be met With in practice, it being assumed that the translator is provided With a` device which ensures that theitwo `extra center, holes produced by stepping back the transmitter,tape are automatically skipped.

ing hole missing at m, Figure Gf normalreversed spacing and Figure greversed spacingtobe neutralizedatw. y

rFrom a consideration ottheseiigures it is 1 apparent that the interpolation .of mark- ,ingand the neutralizing of spacing .to gbe .eiected by the-translator are y (1)"In the case of marking-to `provide amarking currentat the centre hole before v`aespacing hole-Which has nota marking hole opposite `itit there is notA a .markinghole natsuch 4centre hole as indicated inFigures 6a-.and 6c. This-need will arise-in the case of a `.straight tape Whenthe change-over` occnrsfin `the uniddle otar dash andi the spacing lholeis in: theftirstfhole of anew length.

(2) In the case'o spacing--to'neutral-ize a spacing current Which'mayeXist if thereis alspa'cing holeim the tapeuat Athe next centre f ing coilU1 of relay U to the, nega-tive side" of battery Z. It there isa marking signal hole at the neXt centre holel through which Vselector rod P1 rises this rod vP1 only'completes a circuitfor coil V1 ot' relay V which,

4owing to the position of Contact T1 for a `straight tape, is ineffective; Energization of -coil U1 causes tongueU3 to engage its-contact U* (as shown in Figure 5) and-a marking current is transmitted to relay Y as soon as contacts `Y1 Y2 close.

.2. ^Straight tapemarking -hole -missing at m,Figure 6a. Pecker rod P cannot rise but f selector rod R1 Will rise,` in the "spacing hole at'the next centre hole, opening its contact R1.and closing its Contact A circuit is .thus completedfrom the positive side of'battery IZ, contact arm 140,contact R3contact 134, contact arm 138 andthe `coil U1 to the Ynegative-side ofthe battery; The desired marking currentlis thus-transmitted to relay "Y despite the fact thatthe marking signal rholeis missing.

3; Straighttape-norrnal spacing, Figure 6?).` The contactmade by spacing Contact arm S will complete a circuitfor spacing coil `U2 of relay"U Whether there is a signal hole orenot. lPecker rod R passingthrough a hole during the irsthalf ofthe cycle Will completelacircuitfor relay coil V1 which as in (l) is ineffective. V 4l. Straighttape-fspacing to be neutralized at Figure 6c. The selectorrod R1rising the second time passes through 4the signal hole opposite the next centre hole to energize relay coil U1 (asin (2) above), the energization of this coil neutralizing theenergization of'coil U2 by the spacing contact arm iS'.

`5. Reversed'tape-normal marking, Figure 6d. Peckerrod R rising through the hole completes, at its contact `R2 a circuit from the A positive side of the, battery Z, contact B2, contact arm 137 and-through the coil V1 of relay Vtothe negative side ot thebattery. This causestongue V3 to move over ltorcon- 6i. The circuit of spacing coil V2 of relay V is completed at spacing contact arm S as in (3) above.

v8. Reversed tapefspacing to be neutralized at a', Figure 6g. The selector rod P1 rises as in (6) above to eltect the energization of coil V1 Which neutralizesv Coil V2 energized by closing of the spacing lever. Y

VIt Will thus be appreciated that' since the translator interpolates marking currents and neutralizes spacing currents as and When `required in accordance With the rules previously formulated the record made by relay Y or by a reperforator supplied by this relay will be a reproduction ofthe original message on the tape ted into the transmitter-provided that the control switch T4 is actuated to effect reversal at the same intervals and inthe same sense as the control relay transmitting end.

In lorder to explain the action of the translator in actuating its relay so that thereperforator Will produce a tape which is a reproduction of the original tape tedv into the transmitter theoperation ofthe translator as a short length of the tape shown in` Figure 4 is fed into it Will n oW be described in detail. For convenience of description corresponding centre holes in the two tapes of Figures 4 and 2 have been given the same numerals, the eXtra holes vin the received tape (Figure 4) due to the stepping back of the transmitter being given the suffixe. As previously stated the trst section of the received tape (Figure 4) is reversed. vThus theV relay T of the translator `must be set with its tongue T1 engaging itscontact T3 and this relay must be arranged to reverse the translator every ten centre holes, that is at the same intervals as the transmitter was reversed when sending the message.

Referring to the cycle of operations at each center hole as shown in Figure 7 and the eight conditions to be met by the translator as described With reference to Figures 6--6g the star Wheel 100 advances the received tape (Figure 4) during feed period cl-e to the position in which the pecker rods P, Rare opposite center hole l. During the marking period ethe pecker rods P, Rand the selector rods P1. R1 are raised simultaneously the rods P, R passing through the holes opposite the center hole l and the selector Arod Contact arms remaining in engagement O at 1 the Withtheir rest contacts P4, R1 since there are spaces opposite the center hole v2. The'rod R actsV as in condition 5, to cause relay Y to send a marking current to line thus producing the rst portion of the dot7 .above center hole l in vthe reperforated tape (Figure 2) yand the rod Pw is inetective'since with the translator set for reversed tapeA the tongue T1 engages the contact T32 During the spacing periode-b the selector rods P1, R1 are again inoperative and the cam S1 initiatesy the spacing'current which is sent to line by the relay Y during the pick-up period c-b, as in conditions 7, thus completing the dot atcenter hole 1 on the reperforated tapeV (Figure 2).

, 'During the marking period e-f ,at the,

center hole 2 the pecker rods P, R cannotrise but the selector rod P1 rises through the up- 1 er hole at center hole 2 thus causinor a marking current to besent to line, as in. condition 46. and starting the.dash at center hole 2 (Figure 2). During the spacing period the rise of the selector rod P1 through the .upper hole `at the center hole 3 neutralizes the op-i.

eration of the spacing cam S1, Vas in theconv dition 8, sor that the marking current to line continues. i

At center hole the vpecker rod and the selector ro-d R1 respectively rise through the upper hole at center hole 3' and the lower hole at center hole 4 but are ineffective owing to the reverse setting of the translator. The marking current to line thus continuesI during pick-up period fgw During the spacing period a-b'only the selector rod R1 rises so that the spacing cam S1 is eliective (condition 7) to cause a spacing line current dur-- ing v period b-c thus completing the dash by the lower hole at center hole 3 ofthe reperforated tape (Figure 2)'. f i

At centerhole 4 during period e-f the pecker rod R rises through the lower hole and the selector rods P1 R1 through theholes at center hole 5. .l Thus a markingV current `is sentto line during. period .yf-g. Duringk period a- `the spacing cam S1 operates and is not neutralized 'by' selector rod P1 since the neutralizing circuit closed at contact P3 of this rod is opened at back lcontact R1 of current is thus sent to line during period b-o and completesthe dot at center hole 4 (Figure 2). Y

selector rod R1 Which also rises. A spacing 1.15 Y

At center hole 9 during period e-f' the pecler rod R and the selector rod P1 rise thus causing a marking current to be sent to line during period f-g and beginning the dasl During period ca the operation o't the spacing cam S1 is neutralized by the selector rod P1 rising a. second time through the upper hole at centre hole l0 so that the marking current continues during period b-o,

At center hole 10 during period e--f the peeker rod P rises in the upper hole and the selector rod R1 in the lower hole at centerhole lla the marking current thus continues during period During period a--b the spacing cam S operates andsince the selector rod P1 cannot rise at hole 9a a spacing current is sent to line during period iJ-c thus completing the dash at the lower hole ot center hole l0 (Figure 2). y

The reversing relay is then operated during periods c--fl and cZ-e to move the tongue 'lY to the contact T2 and simultaneously the t condenser 'Il discharges through the relay T5 to operate the skipping device so that the holes 11a. and 10a, that is the last center hole before change-over and the first center hole after change-over, produced on the tape (Fi gure Ll) by the stoppin g back ot the transmitter are omitted and the pecker rods l? and R are in line with center hole 1l".

At center hole 1l during period e-f the pecker rod P rises in the upper hole and the selector rod R1 in the lower hole at center hole l2. The peck-er rod P causes a marking current to be sent to line during period as in condition l, the selector rod R1 merely acting to complete a circuit for causing this marking current in parallel with that completed by the pecker rod P (condition 2)'.

,The beginning of the dash at center hole l1 is thus produced on the reperforated tape (Figure 2). During period a-b the selector rod R1 rising in the lower hole at center hole l2 neutralizes the operation of the spacing cam S as in condition Ll, the marking current thus being continued during period -ct At center hole 1:2 during period -f the pecler rod R rises in the lower hole and the selector rods do not rise since there are spaces at center hole 13". The pecker rod R is ineffective so that the markingcurrent continues during period f-g. During period a-b the spacing cam S1 operates and` since it is not neutralized, a spacing current is sent to line which completes the dash7 at the lower hole ot' center hole 12 of the repertorated tape (Figure 2).

The further operation of the translator to send to the reperforator or other instrument corrected impulses corresponding to perforations on the original tape as shown in Figure 2 will readily be understood from the above detailed description in conjunction with the eight conditions del'ined above vhich control the operation ol the translator.

By comparing Figure 2 withFigure 4 or Figure le itwill be appreciated that it will be extremely dir'lic'ult it not impossible to decipher a message mutilated in this way without a key to the points at which reversal takes place, and that, since the reversals can be arranged at any desired regularor irregular intervals and the key can be changed every liewminutes, a very high degree of secrecy is obtained. Furthermore the small loss in speed due to the stepping back ol the transmitter is more thancompensated Yfor by the introduction of' false signals at the'two extra .center holes which are indistinguishable from the real message and assist in rendering the message transmitted indecipherable.

t is to be understood that the above description is `by way ot example only andtliat many modifications may bemade in the transmitting and receiving apparatus Within the scopo oli the invention as defined' in the accompanying claims. For example instead o't.' modifying the transmitter so that the reversing effect obtained therein the pertorator itself could be modified in the saine way so that a tape is prepared bearing the mutilated message, this tape being :ted into an ordinary transmitter andthe key tape or the like controlling the reversals of the pertorator beingemployed with the translator at the receiving end. It will be appreciated that in the case otwireless transmission the reversing transmitter can be employed to control or modulate a wireless transmitter in any suitable mannerinstead o supplying impulses directly to a line wire as in the arrangement described, the wireless receiver being-'arranged to operate a perforating receiver the tape from which is passed through the translator.

lVhat l claim as my invention and desire to secure by Letters Patent is l. In an `automatic telegraph transmitter controlled by signal holes in a perforated tape passing through it, the combination of two pocker rods adapted respectively to engage in upper and lower signal holes in the perforated tape, means for reciprocating the rods alternately, means for reversing at predetermined intervals the order in which the two rods are reciprocated, a source oft marking and spacing electric current, a transmittin()` relay `associated with said source and so controlled by the pecker rods that it transmits a marking current when one pecker rod engages in a signal hole and a spacing current when the other pecker rod engages in a signal hole, and means whereby the pocker rods which respectively control the marking and spacing current transmissions of the relay are reversed when the order in which the said rods are reciprocated is reversed.

2. In an automatic telegraph transmitter controlled by signal holes in a perforated tape passing through it, the combination of two peclzer rods adapted respectively to engage in upper andlower signal holes inthe I perforated tape, means for reciprocating y'the rods alternately, means for reversing at pre- Y determined intervals the order in which the twol rods are reciprocated, means for stepping back the tape during each reversal to.

cause a repetition of signals corresponding to the signal holes on the part of the tape gages in a signal hole and a spacing current when the other pecker rod engages in a signal hole, and means whereby the'pecker rods which respectively control the marking and spacing current transmissions of the relay are reversed when the order in which the said rods are reciprocated is reversed.

3. An automatic telegraph transmitter of Y ,A Y

matic'telegraph system and controlledby,`

the l erforated ta )e t e com irisinur in comlbination a perforated tape having upper and lower signall holes corresponding to a message to be transmitted, means for advancing the tape step by step, two pecker rods adapted respectively to engage in the upper and lower signal holes in the tape, mechanism for reciprocating the rods alternately between each movement of the tape, means for reversing the order in whichthe two rods are reciprocated, a relay device controlling said reversing means, a source of marking and spacing electric current, a transmitting relay associated with said source and so controlled by the pecker rods that it transmits a marking current when one rod passes through a signal hole and a spacing current when the other rod passes through a signal hole, and means whereby the pecker rods which respectively control the marking and spacing current transmissions or' the transmitting relay are reversed when said relay device is actuated.

4. An automatic telegraph transmitter of the perforated tape type comprising in combination'a perforated tape having upper and lower signal holes corresponding to a message tobe transmitted, normally operative means for advancing the tape step by step, normally inoperative means for stepping back the tape, two pocker rods adapted respectively to engage in the upper and lower signal holes in the tape, mechanism for reciprocating the rods alternately between each movement of the tape, means for reversing the order in which the two rods are reciprocated, a relay device controlling said reversing means, a source of marking and spacing current, a transmitting relay associated with said source and so controlled by the pecker rods that it transmits a marking'current when one rod passes through a signal hole and a spacing current when the other rod relay device'. Y Y vtrols theftranslating relay so thatJittra'nspasses through aI signal hole, means whereby` `the pecker rods which'respectivelycontrol themarking and spacing current ltransi'nissions vof the transmitting relay are reversed Y f1 when'sald relay devices is actuated, meansg'70 tor-operating the relay device atpredetermined4 intervals `andgmeans wherebythe tape advancing means is renderedV inoperative and the, tape steppingY back means 1s rendered operative during thefoperation; of the said l5 5.y In atranslator for use in a secret automatic telegraph systemV and controlled fby signal holes in a perforated tape,thecomn bination of' pecker rods and selec-torfrods? adapted to engage inl signal holes, means for reciprocating said rods, 'a translating-relay controlled bysaidrrods andcontrol means wherebyithe operation of the translating `re.-

lay bythe vselector rods eiiects theinterpolation of missing slgnals. n .l Vijf f 6.V In a' translator for use in a'secr'et auto;

signalholes in a'perforatedvtape, the cornbination of pecker ro'dsandr selectorrods adapted to engage in'fadjace'nt holes'i'nfthe tape, means for reciprocating the peckerfrods ing relay, a source of'marking 4a'ndfspacing current associated Ywithsaid relay, means during their lsimult,aneous reciprocation c o'rimi-ts a marking current-,'a'spacing` devicef means for opera-ting the spacing device? after. the simultaneous reciprocation of the pecker and selectonr'ods, means for reciprocating the vselector rods simultaneously with thef it transmits a spacing current and means for-` rendering the: operation of the spacing device ineffective when a selector rod, reciprocated u during such operation, engages in an appropriate signal hole. Y 7. In a translator for'use'in a secret automatic telegraphV system and controlledby signal holes `in a -perforated tape, the "co'mbination of pecker yrods and selector'rods" adapt-ed to engage in adjacent holes inv the tape, means for reciprocating the peckerrods and selector rodsr simultaneously, a translating relay, a source of marking and spacingA current associated with vsaid relay, lmeans whereby the engagement ofV the pecker rods and selector rods in appropriate signal holes during their simultaneous reciprocation con- Aand selector rods simultaneously, avtranslatspacing device, means whereby the spacing@ vdevice controls the translating relayso that device controls the translating relay so that it transmits a spacing current, means for rendering the operation of the spacing device ineffective when a selector rod, reciprocated during such operation, engagesin an appropriate signal hole, and a switching device for reversing the control of the translating relay by the pecker and selector rods.

8. In a translator for use in a secret automatic telegraph system and `controlled by signal holes in a perforated tape the combination of means for advancing the tape step by step,pecker rods and selector rods adapted to engage in adjacent holes in the tape, means for reciprocating the pecker rods and selectorrods simultaneously, a translating relay, a source of marking and spacing current associated With said relay, means Whereby the engagement of the pecker rods and selector rods inappropriate signal holes during their simultaneous reciprocation controls the translating relay so that it transmits a marking current, a spacing device, means for operating the spacing device after the simultaneous reciprocation of the pecker and selector rods, means for reciprocating the selector rods simultaneously with the spacing device, means whereby the spacing d'evice controls the translating relay so that it transmits a spacing current, means for rendering 'the operation of the spacing device ineffective when a selector rod, reciprocated during such operation, engages in an appropriate signal hole, a switching device for reversing the control of the translating relay by the peclrer and selector rods and means operative during the actuation of said switching device for advancing the tape a predetermined number of steps.

9. ln an automatic telegraph transmitter controlled hy signal holes in a perforated tape passing through it,'the combination of means for advancing the tape step-by-step through the transmitter, means for engaging successively the signal holes in thetape at each step, control means whereby said engaging means causes the transmission of impulses in accorda-nce with such signal holes, means operated at predetermined intervals for reversing the order in which the signal holes are engaged at each step, and means for steppingback the tape during each reversal to cause a repetition of signals corresponding to the signal holes on the part of the tape immediatelypreceding the point at Which the reversal takes place.

l0. In a translator for use in a secret automatic telegraph syst-em and controlled by signal holes in a perforated tape, the combination of means for advancing the tape step-by step, means for engaging the signal holes in the tape, a translating relay controlled by saidengaging means, al switching device for reversin the control of thc translating relay bythe engaing means, and means operative Janes HENRY SMART. 

